Abstract the long-term goal of the research proposed here is to develop methods for the isolation and in vitro maintenance of intact colonic crypts from histologically normal human colon tissue and from adenomatous polyps / malignant tumors. The isolated colonic crypts maintained in culture will provide a unique culture system for examining the effects of potential chemopreventive agents in a preclinical setting as well as for examining various aspects of growth regulation in the colon. The same culture system will, hopefully, prove useful for isolation and characterization of stem cells from normal and aberrant crypts. To achieve the goals of this proposal, we will do the following: Specific Aim: Isolate crypts from histologically normal human colon tissue and from adenomatous polyps; develop culture conditions that maintain crypt histological structure and biochemical function and that allow for progression of the histologically-normal crypts through proliferation, differentiation an apoptosis in a spatially and temporally appropriate manner, while allowing for continued growth and expansion of the tissue derived from premalignant adenomatous polyps.